Artificial legs



R. N. BIDWELL ARTIFICIAL LEGS July 3, 1956 5 Sheets-Sheet 1 Filed NOV. 8, 1954 INVENTOR. ROB ERT N. BIDWELL g f j jive/1,.

July 3, 1956 R. N. BIDWELL 2,752,507

ARTIFICIAL LEGS- Filed Nov. 8, 1954 3 Sheets-Sheet 2 I I l 1 INVENTOR.

\ ROBERT N.BIDWELL July 3, 1956 R BIDWELL 2,752,607

ARTIFIC IAL LEGS 3 Sheets-Sheet 3 Filed Nov. 8, 1954 l Jinnah) INVENTOR. ROBERT N. BlDWELL BY jzm United States ARTIFICIAL LEGS Robert N. Bidweil, Madison, Wis.

Application November 8, 1954, Serial No. 467,461

9 Claims. ((11. 3-27) This invention relates to artificial legs and more particularly to artificial knees. The object of the invention is to provide an improved device of this sort which will be of a simple and economical construction, will impose less wear upon the clothing of the user than is the case with known artificial knees and will be silent in action.

A further object is to provide an improved knee which will closely simulate the action of a natural leg in use while safeguarding the wearer against the possibility of falls caused by the knee being inadvertently and unexpectedly thrown forward.

Briefly stated the invention resides in providing an automatically acting friction lock between the upper or thigh portion of the leg and the lower or shank portion thereof, which lock comes into action as the weight of the user is brought to bear upon the shank, the locking action being automatically released as the weight is removed. The shank portion is then rendered free to swing forward in the act of walking.

I am aware of the fact that friction locks in artificial knees are not broadly new but as this description proceeds it will be seen that the construction of the device of this application presents advantages not to be found in any known device of this nature. These advantages can be best understood and appreciated by reference to the accompanying drawing, wherein:

Fig. l is a side elevation of a knee constructed in accordance with the invention;

Fig. 2 is a transverse vertical sectional view upon line 2-2 of Fig. 1;

Fi 3 is an enlarged fore and aft central vertical sectional view with the thigh portion moved to the limit of its forward movement with respect to the shank portion;

Fig. 4 is a detail view showing the complete assembly its relation to an artificial leg;

Fig. 5 is a view like Fig. 3 illustrating a modification, hereinafter described;

Fig. 6 is a sectional View through the neoprene block illustrating the modification in its relation thereto; and

Fig. 7 is a perspective view of the bearing plate of the modification.

Like numerals designate corresponding parts in all of the figures of the drawings.

In the drawings 5 designates an upper socketed element, referred to herein as the thigh element, the upper portion of which receives the thigh or stump portion 5a of the leg. 6 designates the lower or shank portion of the artificial leg, the open upper end of which has secured therein the lower tubular end 7 of the lower or shank engaging member of the artificial knee.

This lower member 8 comprises and is stifiened and strengthened by a yoke 9 which extends around the leg and comprises. upturned side portions 10 which terminate in ears 11-. These ears are traversed by and support a knee bolt 12, said bolt having threaded engagement at 13in one of saidears. At its other end the bolt is slightly tapered at 14 to enter the other of said ears and is in- Patented July 3, 1956 ternally threaded for the reception of a lock screw 15.

Knee bolt 12 passes through a split bronze bushing17. A binding screw 18 which engages ears of said bushing, provides means for adjusting the freedom of rotation of bolt and bushing with respect to each other. A fixed rod 19 extends between and is secured to the upturned portions 14 of the shank portion of the knee and in conjunction with a rubber block 20 constitutes a stop for limiting the forward movement of the thigh portion with respect to the shank portion of the knee. The rubber stop block lies at the front end of an arcuate channel 21 said channel being concentric with bolt 12 and lying between the main body portion 22 of the part 5 of the knee and a separate curved plate 23 that is welded or otherwise secured in place. An opening 24 formed in the elements 22 and 23 permits the entry of a screw driver for adjusting the bearing of the split bushing and bolt with respect to each other.

The plate 23 carries an arcuate brake shoe 25 made of neoprene, rubber or any other material having the desired frictional, wear resistant and cushioning characteristics. This brake shoe is concentric with bolt 12 and it coacts with an arcuate brake shoe 26 that is secured upon an integral web 27a of the shank part of the knee. Brake shoe 2 6 preferably has an arcuate upper face adapted to have the maximum of gripping engagement with brake shoe 25. The arcuate channel 21 is enough greater in its width, than the diameter of rod 19, that the portion 5 may move downwardly toward the shank portion. 6 of the leg Without interference of said rod. Such downward movement takes place when in the act of taking a step the user swings the thigh portion forwardly toward the position of Pig. 3. When this happens a stout neoprene block 27 of ovaloid form into which the bronze bushing is molded, as shown in Fig. 3, is resiliently compressed, permitting part 5 and the stump to have a limited downward movement toward shaft 12, said shaft being supported against such downward movement by its mounting in ears 11.

While it is desirable that an eflicient locking engagement between the parts be established as soon as the weight of the user begins to be brought to bear upon the lower leg, whereby to prevent accidental forward movement of the knee, it is also very desirable that the locking action.

at its sides against lateral spreading it follows that more.

compression against the resilience of the block, will be. had, than would be the case with say a block, circular in cross section and containing only the same volume of neoprene. in the latter case we would have more of a mere lateral displacement of material than a compression against resilience. quick reaction of the structure to released position when the weight of the wearer is removed from the knee.

At its ends the block 27 projects enough beyond the. bronze bushing to contact the inner faces of ears'll and prevent metal to metal contact between said ears and any surface of the part 5. Thus the joint is rendered completely silent in action, no squeaks or other noises resulting from the flexing of the knee. When the knee is fully flexed, as for example when the wearer kneels, the rubber brake shoe 25 presents to the contacting clothing a surface which will neither wear or cut said clothing- Further this rubber member provides a cushion for the person who is kneeling. Some. prior art devices cannot be brought to kneeling position at all and some after hav- My described arrangement yields a.

ing been brought partly to kneeling position pinch the clothing when the leg again straightens out. The stop bar 19 tying the sides together, not only adds to the general rigidity and strength of the structure but it adds to the stability of the knee and the safety of the wearer during the bending action. Further this stop structure is so enclosed as to present no danger of tearing the clothes of the wearer.

A further feature of advantage lies in the fact that this device permits the fitting of a longer stump than is possible with many of the devices of the prior art. The stump may be fitted well down into the socket of part 5 and close to bolt 12. This proximity of stump to pivot makes for greater safety and ease of control.

The modification illustrated in Figs. 5, 6 and 7 embodies simple means for not only adjusting a brake action of the bronze bushing upon the knee bolt but also for providing a simple and inexpensive means which resists any tendency toward lateral flexing of the parts at their point of juncture. In these figures the same reference characters have been applied where the parts are the same as in the other figures of the drawings. In the modification the knee bolt 12 is embraced by a bushing 17a of the nature of bronze bushing 17 but diflering therefrom that from the edge of its split portion there project an ear 18a and a bearing plate 30. The ear and plate are traversed by a binding screw 31 which serves to bind the bushing more or less firmly upon the bolt.

The outer edge of bearing plate 30 is pierced for the passage of screws, one of which is indicated at 32. These screws bind the outer portion of the plate 30, together with a pair of cushioning strips 33 against the under face of the ledge 34 of the thigh portion of the leg. This arrangement effectively resists any tendency of the thigh portion to rock sidewise in either direction, along the axis of the knee bolt.

It will be observed that the presence of the uppermost strip 33 spaces the upper face of the plate away from ledge 34 far enough to leave the space 35. Thus the necessary vertical movement of the thigh toward the leg portion can take place as the block 27 is compressed.

Access may be had to the screws 31 and 32 for adjusting them by removing the screws 23a which hold the part 23 in engagement with the remainder of the thigh portion.

The metallic body portions of the structure are preferable made of aluminum. This renders the limb of light weight and avoids the labor such as rawhiding, painting, doweling, etc. inherent in some artificial limb-s. My improved structure avoids the use of springs, latches and the like and it may be fitted without excessive cost to some of the limbs already on the market. It may be used on either the right or left leg and can be used with widely varying calf measurements. As a result dealers will not be required to stock as many sizes as is now the case. The structure comprises only a few, simple and easily assembled parts. This reduces initial cost and lessens the cost of replacements. Any adjustments in use may be made by any person of average intelligence. The walls of the portion 5 which surround and closely embrace the neoprene block 27 constitute a chamber 5x which extends entirely across the portion 5 and is open at each end. Thus the block is readily removable for replacement or repair, if that should become necessary. The sides of the portion 5 are provided with recesses 5b in which the ears 11 are disposed. This brings the thigh and shank portions flush with each other over the area occupied by bolt 12 and eliminates any projections which would catch, tear or wear the clothing.

The invention is not limited to the precise construction set forth but includes whatever changes fairly fall within either the terms or the spirit of the appended claims.

Ielaim:

1. An artificial knee comprising a socketed stump re ceiving thigh portion having a chamber extending completely therethrough and open at its ends, a block of resilient material extending throughout the length of said chamber, a shank portion having a pair of upstanding ears which overlie the ends of the resilient block, a knee bolt passing through said block and having its ends mounted in said ears, brake shoes carried by the shank portion and lower end of the thigh portion, the thigh portion having its side walls recessed for the reception of said ears, said recesses being of such vertical amplitude as to permit downward movement of the thigh portion and consequent compression of the resilient block under the weight of the user to bring said brake shoes into engagement with each other.

2. An artificial knee comprising a socketed stump receiving thigh portion having a chamber extending completely therethrough and open at its ends, a block of resilient material extending throughout the length of said chamber, a shank portion having a pair of upstanding ears which overlie the ends of the resilient block, a knee bolt passing through said block and having its ends mounted in said ears, brake shoes carried by the shank portion and lower end of the thigh portion, the thigh portion being provided with an arcuate slot at its rear portion, said slot being concentric with said knee bolt, a cushioning member located at an end of said slot and a stop rod extending across and rigidly afiixed to the shank portion and passing through said slot, the width of the slot being enough greater than the diameter of said rod to permit movement of the thigh portion toward the shank portion, whereby to bring said brake shoes into engagement with each other.

3. An artificial knee comprising a socketed stump receiving thigh portion having a chamber extending completely therethrough and open at its ends, a block of resilient material extending throughout the length of said chamber, a shank portion having a pair of upstanding ears which overlie the ends of the resilient block, a knee bolt passing through said block and having its ends mounted in said ears, brake shoes carried by the shank portion and lower end of the thigh portion, in combination with a metallic bushing that is embedded in the resilient block, and through which said bolt passes.

4. An artificial knee comprising a socketed stump receiving thigh portion having a chamber extending completely therethrough and open at its ends, a block of resilient material extending throughout the length of said chamber, a shank portion having a pair of upstanding cars which overlie the ends of the resilient block, a knee bolt passing through said block and having its ends mounted in said ears, brake shoes carried by the shank portion and lower end of the thigh portion, the block of resilient material being of ovaloid form in cross-section and elongated in the direction of its height.

5. An artificial knee comprising a socketed stump receiving thigh portion having a chamber extending completely therethrough and open at its ends, a block of resilient material extending throughout the length of said chamber, a shank portion having a pair of upstanding cars which overlie the ends of the resilient block, a knee bolt passing through said block and having its ends mounted in said ears, brake shoes carried by the shank portion and lower end of the thigh portion, in combination with a bearing bushing located in and closely engaged by said block and upon which the knee bolt has its bearing, said block being of ovaloid form in cross section and elongated in the direction of its height, the bushing and bolt passing longitudinally therethrough at a point ad jacent its bottom.

6. An artificial knee comprising a socketed stump receiving thigh portion having a chamber extending completely therethrough and open at its ends, a block of resilient material extending throughout the length of said chamber, a shank portion having a pair of upstanding cars which overlie the ends of the resilient block, a knee bolt passing through said block and having its ends mounted in said ears, and brake shoes carried by the shank portion and lower end of the thigh portion, a metallic bushing embedded in said resilient block through which said knee bolt passes, said bushing being split, and a binding means for tightening said bushing upon the bolt.

7. A structure as recited in claim 6 in combination with a bearing plate projecting from said bushing and means for securing said plate to the thigh portion in a position to resist tendency of the thigh portion to tip laterally.

8. A structure of the character described comprising a thigh portion and a leg portion, a knee bolt hingedly uniting said portions, a block of resilient material, through which said knee bolt passes, a bushing frictionally em- 15 2,509,586

bracing the knee bolt, means for adjusting the frictional engagement of the bushing on the knee bolt, and a later"- ally extending plate carried by the bushing upon which the rear part of the thigh portion rests, said plate being or" such length in the direction of the axis of the knee bolt as to prevent sidewise tipping of the thigh portion with respect to the leg portion.

9. A structure as recited in claim 8 in combination with a body of resilient material between said rear part and the outer portion of the plate.

References Cited in the file of this patent UNITED STATES PATENTS 2,282,952 Erickson May 12, 1942 Caron May 30, 1950 2,588,013 Kleinekathofer Mar. 4, 1952 

